This invention relates to a meat pumping process employing soy protein isolate and, more particularly, a non-gelable, soy protein isolate which is rapidly dispersible in water to provide a portion of the pumping medium, i.e., "brine".
The pumping of hams with brine, sometimes referred to as "pickle", probably antedates recorded history. The most common salt employed is sodium chloride which provides curing (color), preservative (shelf life) and organoleptic (taste) functions. Also, for a long time, the salt has been augmented by sugar which also provides the same type of functions. Because the addition of the brine permitted the possible addition of excess water, most authorities have provided stringent regulations on the weight increase in hams due to salt solution addition. However, there was and is a natural limitation as to the amount of water which can be introduced into a ham for the purpose of preservation and taste, i.e., moistening, because of loss on cooking. This, irrespective of the type of curing salts, common supplements to the sodium chloride being sodium nitrite and sodium erythorbate, both of which enhance color.
Extensive investigation was made of various phosphates which were believed to have the ability to bind additional water in meat fibers--and increasingly following World War II, various polyphosphates were added to the brine solution. None of the salts in the brine provided any nutritional value, particularly of a protein nature.
Starting in the mid 1960's, soy protein isolate was viewed as an especially attractive supplement to the brine to permit the introduction of more fluid while maintaining the nutrition level, particularly relative to protein. Soy protein isolate (sometimes referred to as "isolated soy protein"), is defined as the major proteinaceous fraction of soybeans prepared from high quality, sound, clean dehulled soybeans by removing a preponderance of the non-protein components and containing not less than 90% protein (N.times.6.25) on a moisture free basis. This definition was accepted by the United States Food and Drug Administration as well as the Technical Service Division, Consumer and Marketing Service, United States Department of Agriculture (1961).
Notwithstanding the opportunity of introducing more effective brine through the use of soy protein isolate, the technique was not formally recognized by the United States Department of Agriculture until May 28, 1976. This recognition was justified as meeting the need to better utilize existing sources of protein in replacing meat with protein from less costly sources. Some commercial activity utilizing soy protein isolate as part of the brine had occurred in the United States in the ten years preceding formal recognition but the bulk of the commercial activity has occurred in Europe.
Starting in the mid-1960's, a large number of ham processors augmented the brine with a soy protein isolate marketed by Central Soya Company, Inc. under the make "PROMINE". This soy protein isolate conforms to the foregoing definition, being prepared from selected, defatted soybean flakes obtained by the solvent extraction processing of high quality, sound, clean, dehulled soybeans. These flakes are treated in mildly alkaline aqueous medium to extract the soluble protein constituents, carbohydrates, mineral matter, and other soluble minor flake components from insoluble matter.
The protein-containing extract is then separated from residual flake material and subsequently acidified to about pH 4.5 with food-grade hydrochloric acid. This results in the precipitation of the major globulin fractions of the soybean protein as a finely-divided white curd. This curd is then separated, washed with water, and dispersed at about pH 7.0 with food-grade sodium hydroxide. The resulting protein dispersion is spray dried.
A typical soy isolate augmented brine employed over the years in Europe included 4% isolate, 10% salts including the chloride and nitrite, 3% phosphate and 3% sugar including monosodium glutamate with the remainder water. In some cases, higher or lower concentrations of isolate were employed. The concentration of the isolate was generally a matter determined by customer taste and it was found that there were distinct preferences in different countries. For example, Spanish ham processors desired a less pink ham than those in France. A variety of differences in taste, appearance, etc. could be found in the products in the other countries employing isolate during the past decade, viz., Holland, Poland, Norway, Denmark, Sweden, etc.
This isolate augmented brine has been pumped into hams both via the arterial-venous system and by stitch pumping. Stitch pumping has come to be preferred because it is faster and more economical, and is more reliable, not being subject to vein or artery rupture or blockage.
Generally the concentrations of isolate in the brine were maintained at a level of about 5%--this primarily being due to the difficulty in rapidly developing the isolate dispersion and thereafter handling the same incident to pumping. It will be appreciated that a ham processing plant is not normally characterized by the refinements and techniques of the analytical laboratory so that higher isolate concentrations which were feasible under more controlled conditions were normally avoided because of the essential ruggedness of the working conditions in ham processing plants.
It was felt desirable to be able to increase the concentration of isolate in the brine--for a number of reasons. Principally, this would permit increasing the effective weight of hams with proportionately less costly ingredients. However, to be acceptable, the water-isolate relationship should be such that after cooking, the isolate was present in the remaining water at a level comparable to the percentage of protein actually present in the ham, viz., 17-20%. So it was not just a matter of utilizing the water binding power of isolate--the isolate concentration had to be stepped up as more water was employed.
The increase in water was beneficial in a different sense--it made the inclusion of the other brine constituents easier. For example, the amount of salt, sugar, phosphates, etc. employed is dependent on the weight of the ham to be cured. With only a small amount of water addable, the constituents are present in relatively concentrated form. For example, in pumping a 10 lb. ham with 10% of brine, only 1 lb. of water is available as the solvent. This meant that approximately 0.025 lbs. of the phosphates (the most difficult of the constituents to dissolve) had to be dissolved in the 1 lb of water. However, if the pump could go to 50% of the green weight of the ham, 5 lbs. of water would be available to dissolve the same 0.025 lbs. of phosphates. Thus, there was real interest in increasing the concentration of the isolate in the brine.
The deterrent to this increase has been the viscosity of the isolate solutions at higher concentrations. Even with stitch pumping, the brine could not be used advantageously--plugging the needles and failing to diffuse completely through the muscle structure. For example, an upper limit of 10% isolate in the brine was recognized in U.S. Pat. No. 3,989,851, and a level of 7-8% was exemplified. And even to get this increase it was necessary to first dissolve the isolate with prolonged, violent agitation and thereafter add the remaining constituents in dry form. This posed an additional problem relative to the phosphates which are difficult to get into solution--the preferred manner being to dissolve the phosphates separately and then add the phosphate solution to the isolate solution. But this was self-defeating because the additional water associated with the phosphates would reduce the effective concentration of the isolate.
Further, it was long recognized in the commercial art that it was imperative to add the isolate to the water before the salts in order to get a stable solution--and this even in the lower isolate concentrations.
Thus, it would be advantageous to provide a brine that would (1) permit the use of higher isolate concentrations, (2) permit addition of salt solutions, particularly the phosphates, (3) achieve rapid solution of the isolates without the need for expensive agitation equipment, and (4) even, in some cases, avoid the criticality of adding the isolate first.
This had been achieved according to the instant invention by employing a unique isolate, more particularly one that provides a relatively low viscosity brine even with isolate concentrations above 12%. Further, in contrast to the isolate recommended in U.S. Pat. No. 3,989,851, the isolate of this invention is non-gelable upon heating. The dispersability of the non-gelling isolate is improved through augmenting the isolate with a minor amount (up to about 2%) of a polar lipid material such as a lecithin, a monoglyceride, a monodiglyceride, or a monopropylene glycol ester. Additional details thereon can be found in the co-pending application of Meyer and Whitney, Ser. No. 761,425, filed Jan. 21, 1977.